Since you are new to this car I would sure use the Trans-x ( but at the rate suggested on the side of the can... (find out how much fluid your trans has before you go to the store... ) it may take two cans to get the percentage suggested....
I would want the trans holes cleaned by the Trans-x ... then when I take the fluid out and put new fluid and filter I would feel much better about the condition of the inside of the trans.....ie, taking the old fluid out would evacuate whatever the Trans-X dissolved out of the valve body...